While running valgrind on osquery it reported an invalid memory access in the curl_certificates table. There is a read and potential write 1 byte past the end of a memory buffer when stripping trailing newline from the end of the formatted X509 extension name. In this PR I remove the spurious check past the end of the buffer and also fix an issue where, if a newline had been found at the end of the buffer, the output included a NIL byte at the end instead of actually shrinking the string as intended.